Abstract: The flexural properties and fracture toughness of several CVI-SiC/SiC composites with various fiber/matrix interlayers and SiC nanowires were investigated comparatively. The results indicate that interlayer is very important to the mechanical properties of the composites. A 120nm thick carbon interlayer increases both the strength
and toughness twofold. When the single carbon interlayer is replaced by a C/SiC/C tri-interlayers but with same total amount of carbon, the composite shows no significant changes of the properties. Preliminary study on the composite with SiC nanowires in the matrix shows that SiC nanowires possesses very high reinforcement efficiency, providing the composite high strength and toughness.

Key words: CVI, SiC/SiC composite, SiC nanowire, interlayer